1. Field of the Invention
The present invention relates to a chaotic signal transmission device and, more particularly, to a parallel sequence spread spectrum type chaotic signal transmission device adapted for converting a serial data signal into a parallel data signal and transmitting a chaotic signal according to the converted data signal.
2. Description of the Related Art
In general, a chaotic signal is anon-periodical signal that does not have a particular phase and has wideband characteristics. A general sinewave signal has a regular phase over time, which may be distorted or canceled out when an anti-phase interference signal is added thereto. However, in case of the chaotic signal, because it does not have a specific phase, although an anti-phase signal or an interference signal is introduced, no interference occurs, having the advantage that the data signal bearing information can be protected. In addition, in terms of frequency analysis, the chaotic signal has high energy efficiency with a uniform size regardless of the period at a wideband range.
When the chaotic signal is used as a carrier, it has a small spike, so coding such as time hopping is not required in a modem, and a simple transmission device or a reception device can be implemented by using ON-OFF Keying, a simple modulation method.
Because the chaotic signal can be controlled through a small change of system, a communication system with improved power efficiency can be implemented by using the chaotic signal. In addition, because the chaotic signal essentially has a continuous spectrum spreading to a broad frequency band, it can be used for modulation with an energy spectrum without a loss over the wideband. Owing to such advantages of the chaotic signal, there have been many efforts to use the chaotic signal for a transmission device or a reception device using ultra-wide band.
For transmission of the chaotic signal, the related art employs a direct sequence spread spectrum (DSSS). In this method, when multiple users are intended to be supported while maintaining the wideband characteristics, the DSSS has a transmission speed slower than 5 Mbps.
However, recently, entertainment and medical instruments based on a wireless body area network (WEAN) requires a transmission speed of 5 Mbps or faster. Failing to meet such speed requirement, the related art DSSS type chaotic signal transmission device cannot be employed for the WBAN-based entertainment and metical instruments.